<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Flex布局测试</title>
    <style>
        html,body{
            width: 100%;
            height: 100%;
        }
        .top{
            display: flex;
            margin: 20px;
            width: 100%;
            height: 250px;
            justify-content:space-around;  /*水平对齐方式*/
            align-items: center;/*垂直对齐方式*/
            background-color: red;
        }
        .item{
            width: 100px;
            height: 100px;
            background-color: white;
        }
        .item1{
            margin-left: 50%;
        }
        .bottom{
            display: flex;
            margin: 20px;
            width: 100%;
            height: 100%;
            justify-content:space-around;  /*水平对齐方式*/
            align-items: center;/*垂直对齐方式*/
            background-color: red;
        }
        .left{
            height: 90%;
        }
        .left-top{
            background-color: white;
            height: 700px;
            width: 500px;
        }
        .right{
            height: 90%;
        }
        #item{
            height: 100px;
            background-color: white;
            width: 900px;
        }
        #left-item{
            margin-top: 40px;
            width: 500px;
            display: flex;
            justify-content:space-between;  /*水平对齐方式*/
        }
        .left-item{
            width: 80px;
            height: 80px;
            background-color: white;
        }
    </style>
</head>
<body>
    <div class="top">
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
        <div class="item item1"></div>
    </div>
    <div class="bottom">
        <div class="left">
            <div class="left-top">左上</div>
            <div id="left-item">
            <div class="left-item">左下</div>
            <div class="left-item">左下</div>
            <div class="left-item">左下</div>
            </div>
        </div>
        <div class="right">
            <div id="item">右边</div>
            <div style="margin-top:20px"></div>
            <div id="item">右边</div>
            <div style="margin-top:20px"></div>
            <div id="item">右边</div>
            <div style="margin-top:20px"></div>
            <div id="item">右边</div>
            <div style="margin-top:20px"></div>
            <div id="item">右边</div>
            <div style="margin-top:20px"></div>
            <div id="item">右边</div>
            <div style="margin-top:20px"></div>
            <div id="item">右边</div>
        </div>
    </div>
</body>
</html>